﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Data;

namespace Elentok.Common.Wpf.ValueConverters
{
  /// <summary>
  /// Converts from value to <see cref="Boolean"/>.
  /// (If the value is <c>null</c>, returns <c>true</c>; otherwise <c>false</c>).
  /// </summary>
  public sealed class IsNullToBooleanConverter : IValueConverter
  {
    /// <summary>
    /// Converts a value.
    /// </summary>
    /// <param name="value">The value produced by the binding source.</param>
    /// <param name="targetType">The type of the binding target property.</param>
    /// <param name="parameter">The converter parameter to use.</param>
    /// <param name="culture">The culture to use in the converter.</param>
    /// <returns>
    /// If the value is <c>null</c>, returns <c>true</c>; otherwise <c>false</c>.
    /// </returns>
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
      return (value == null);
    }

    /// <summary>
    /// Converts a value.
    /// </summary>
    /// <param name="value">The value that is produced by the binding target.</param>
    /// <param name="targetType">The type to convert to.</param>
    /// <param name="parameter">The converter parameter to use.</param>
    /// <param name="culture">The culture to use in the converter.</param>
    /// <returns>
    /// A converted value. If the method returns null, the valid null value is used.
    /// </returns>
    /// <exception cref="NotImplementedException">Method is not implemented.</exception>
    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
      throw new NotImplementedException();
    }
  }
}
